A balloon catheter is a device with an elongated shaft that carries an inflatable balloon. Typically, the shaft is delivered into a narrow body lumen with the balloon in a low profile deflated state. When the treatment site is reached, the balloon is inflated to its full diameter. After treatment is complete, the balloon is again deflated, hopefully to a small diameter profile, and the catheter is removed from the body. Inflation of the balloon may be effective to, for example, dilate the lumen, deliver a stent to the site, block the lumen, at least temporarily, stabilize the catheter, or deliver drugs to the lumen walls.